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Abstract: Multiwall carbon nanotubes were synthesized using the catalytic chemical vapor deposition (CVD) technique followed by an oxidative purification process. The nanotube modified by functional groups were connected by pre-synthesized oligonucleotides in solution. The material thus obtained was characterized by various microscopic methods. The preparation of nanotube chips is discussed. [Copyright &y& Elsevier]

Abstract: This study explores the possibility of converting a self-supporting, randomly aligned, low impedance multi-wall carbon nanotube (MWCNT) paper into a resistive temperature measurement unit working at ambient pressure in air in the 25–70°C range. Thermosensitization was achieved by decorating the surface of the films with pyroelectric CsNO3 or LiNbO3 crystals. Assuming a linear temperature response, temperature coefficient of resistance values of −0.158%°C−1 and −0.246%°C−1 were calculated for CsNO3 and LiNbO3 doped films, respectively. The corresponding temperature measurement accuracies (2.2°C and 3.0°C) are acceptable for some applications but the precision of the temperature measurement needs to be improved. [Copyright &y& Elsevier]

Abstract: Silicon nitride based composites with different amount (1, 3 or 5wt%) of carbon nanotubes have been prepared by using hot isostatic pressing. Composites with 1, 5 or 10wt% carbon black and graphite have been manufactured, in comparison. Optimisation of the manufacturing processes has been performed, providing intact carbon nanotubes during high temperature sintering. In the case of 1 or 3 wt% carbon nanotube addition, the increase of gas pressure during sintering resulted in an increase of bending strength. It was found that microstructure features achieved by properly designed sintering parameters are the main responsible factors for the strength improvements. Scanning electron microscopy showed that carbon nanotubes have a good contact to the surface of silicon nitride grains. The electrical properties of silicon nitride matrices with carbon addition may change essentially. [Copyright &y& Elsevier]

Abstract: Trititanate nanotubes were prepared from anatase TiO2 in 10M Na2S solution kept at 130°C for 2 weeks. On the basis of this reaction, we devised a novel synthesis method which allows the preparation of titanate nanotubes decorated with CdS nanoparticles in one step. The key feature of the suggested method is controlling the rate of CdS formation by introducing Cd2+ ions as a Cd–EDTA complex into the synthesis mixture. The nanotubes obtained are several hundred nm long, tend to aggregate into rod-like structures and are fully covered by CdS nanoparticles with an average diameter of ∼5.3nm. [Copyright &y& Elsevier]

Abstract: Synthesis of carbon nanotubes (CNTs) from the template molecules of the Si-MCM-41 and Al,Si-MCM-41 mesoporous silicates were investigated. The generation of nanotubes was carried out by graphitization, i.e. applying high temperature treatment of the MCM-41 samples in inert gas atmosphere. The as-synthesized and graphitized samples were characterized by several spectroscopic and physico-chemical methods such as IR and MAS NMR spectroscopy, XRD, TEM, and BET. [Copyright &y& Elsevier]

Abstract: Mesoporous MCM-41-carbon nanocomposites were prepared in several Si:C ratios from amorphous active carbon, graphite and multi-wall carbon nanotube carbon sources. A complete morphological characterization of the samples was performed using XRD, TEM, SEM, N2 adsorption and surface hydrophilicity measurements. Specific surface area, pore size distribution, surface fractal dimension and the dimension of capillary condensation were calculated and the adsorption excess isotherms of the ethanol–cyclohexane system were measured. Our results show that the three carbon types give rise to rather different composite morphological features. On this basis the fine tuning of carbon–silicate composite properties by design appears feasible. [Copyright &y& Elsevier]

Abstract: A systematic study on the morphological changes experienced by multi-wall carbon nanotubes during long-time ball milling in a vibrating mill was performed. Samples were collected in the time interval 0–200h and analyzed with TEM and N2 adsorption. The change of the mean nanotube length with time could be approximated with a second-order exponential decay function. The length distribution function changed from the original log-normal to normal after 140h of milling. Specific surface area, surface fractal dimension, the dimension of the capillary condensation and the pore size distribution (PSD) curve were calculated from the N2 adsorption isotherms. These morphological descriptors all experienced characteristic changes after ∼40h of milling: the specific surface area decreased, the fractal dimension increased and the maximum of the PSD curve shifted downwards by ∼0.5nm. Results indicate that ball milling of carbon nanotubes is a rather complex process and that it can cause several morphological changes to samples besides the well-known cutting effect. [Copyright &y& Elsevier]

Abstract: Ion-exchangable titanate nanotubes synthesized by the alkali treatment of TiO2 (anatase) were rendered photochemically active by decorating them with CdS nanoparticles through a simple wet chemical process. HRTEM, Raman and IR observations suggest that the activation could be caused by the strong coupling between the nanotube and the nanoparticles. [Copyright &y& Elsevier]

Multi-walled carbon nanotubes have been shortened by ball milling under ambient conditions. Detailed high-resolution TEM studies of the carbon nanotube ends showed a high-percentage of carbon nanotubes had partially or completely collapsed openings. Their stability was also discussed. Based on the morphology of the broken ends, different mechanisms for carbon nanotubes cleavage under ball milling conditions were proposed. [Copyright &y& Elsevier]

Catalytic decomposition of acetylene was studied under reduced pressure in a batch reactor over catalyst samples, which previously showed outstanding activity and selectivity in carbon nanotube formation in a fixed-bed flow reactor under atmospheric pressure. It was found that activity depends on the nature of the catalyst sample at lower acetylene pressure. Characterization of the samples was carried out by transmission electron microscopy and X-ray diffraction. Concerning the quality and the graphitization of carbon nanotubes, selectivity showed a strong dependence on the initial pressure. With decreasing pressure the formation of fullerenes was obtained. To detect the amount of fullerenes and polyaromatic hydrocarbons, Soxhlet extraction followed by high pressure liquid chromatography (HPLC) mass spectrometry (MS) analysis was carried out. Certain catalyst samples showed activity in fullerene formation independent of pressure. HPLC results support a mechanism for catalytic C60 formation via polyaromatic hydrocarbons as building blocks. [Copyright &y& Elsevier]

The present text describes an investigation of XPS study of multiwall carbon nanotube (MWNT) synthesis. The aim of the investigation was not only to improve the reaction activity by mixing nickel with vanadium, but also to understand the formation mechanism of the nanotubes. Carbon nanotubes were produced by catalytic chemical vapor deposition (CCVD) of acetylene on transition metal containing catalysts supported on zeolite ZSM-5. The samples were characterized at two different levels. At the nanoscale, they were studied by transmission electron microscopy (TEM), while at macroscopic scale mainly XPS was used to investigate the changes during the reaction. [Copyright &y& Elsevier]

Catalytically prepared multiwall carbon nanotubes (MWNTs) were cut and functionalised by mechanical and/or chemical methods. Products were characterised by transmission electron microscopy, infrared spectroscopy and BET method. It can be concluded that physical and chemical breaking procedures complete each other very well. With certain MWNT samples containing surface oxides preliminary investigations were done for testing them as catalyst support. [Copyright &y& Elsevier]

Multiwall carbon nanotubes (MWNTs) were synthesized by a novel method of mesoporous MCM-41 and MCM-48 silicates in the absence of any metal traces. A transmission electron microscopy (TEM) study shows that the diameter distribution of the obtained carbon nanotubes is very narrow – 5–6 nm in diameter and 200 nm in length – compared to nanotube samples produced by other catalytic chemical vapor deposition (CCVD) techniques. [Copyright &y& Elsevier]